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Here's what I want, and given the capabilities of the Optiview controller I don't think it's too much to ask. Either A: give me a minimum capacity limit such as 15%. This will be enough to drive the LWT down to the disable setpoint and cycle the machine off when the load goes away. Or B: when a stall is detected and the VGD is closed for 30 minutes, modulate the HGB open to eliminate the stall. Why can't it do that?

Another oddity: the 2200 ton YK chillers at the same site continue to pull down when the load goes away, and then they cycle off. Is it because they are designed for a 60°F LWT?

Efficiency is a concern, but I'm more concerned about the compressor self-destructing. It sounds like a large steam engine and runs 104°F discharge superheat. That can't be good.

You want an engineered control system. So do the rest of us in any odd situation we find ourselves in. You're not going to get it. There's things about Tranes that stink, too. If it would do what you want, it would sit there and beat the rotor bars in the motor and the journal bearings into scrap metal from excessive starts. I've personally witnessed this on more than one process chiller.

This is not a chiller problem from what I'm hearing - this is a problem of system design and unwillingness by men to shut the machine off when not needed. It's the little brown, double-ended switch at the bottom right of the keypad. Turn it off.

You're right, it's not good to run under the conditions you describe. Turn it off.

The 2200 TR's load is going away completely and the smaller units load is only dropping to the same point as the idle system capacity of the chiller. Turn it off.

No, BOTH machines' load is going away completely. The 2200 pulls down and shuts off. The 750 just sits there and runs. I shut the chiller down for 30 minutes and the water (brine) temps stayed at 32°F. That's how I know there is NO load.

So I guess the consensus is they're just going to have to shut the machines off when there's no load. So why in the world did York even provide a Disable Setpoint?! What could this possibly be used for if the machine can never reach setpoint - 1°? The only thing I can think is if you have multiple chillers on the same loop and another chiller has a lower LWT setpoint. But I only have one chiller (for now, they're going to add another) so I'm screwed.

So, how long can this thing surge like a locomotive before the compressor is toast?

If any thread needs to be in the PRO FORUM, this is it. There is no way a technical conversation as deep as is warranted here should be in the open forum.

I agree. Sounds like deja vu. But I don't think it'll get much deeper. The customer didn't need a chiller of the size they have, and they need to turn the one off that they bought. Thousand different ways to do that, but instead of turning it off the chillers a piece of crap because the compressor engineer at York doesn't agree with the guy that's been hired to work on the chiller.

MFT: I'm sorry as I can be if you don't like what's being said, but I had a 50° delta T (90° to 40°), 5 pass, 600TR PACKAGE chiller one time that ran during the winters with 43° entering water from the settling ponds at the mill. Chiller logged around 28,500 starts in 6 years (2300 volt A/L start). Four motor rebuilds for busted rotor bars before the thing finally extruded the front HS bearings out of it. Rebuilt the two sitting in the same plant on the same process for the same reasons, first one was replaced because of the halogen fire when the impeller drug on the diffuser. It wasn't the chillers fault...

Coming across a poor application, that has frustrated the customer and given the manufacturer a bad reputation (in the customer's eye), is an opportunity for a tech to really shine. They are not to be squandered....

Coming across a poor application, that has frustrated the customer and given the manufacturer a bad reputation (in the customer's eye), is an opportunity for a tech to really shine. They are not to be squandered....

So I guess the consensus is they're just going to have to shut the machines off when there's no load. So why in the world did York even provide a Disable Setpoint?! What could this possibly be used for if the machine can never reach setpoint - 1°? The only thing I can think is if you have multiple chillers on the same loop and another chiller has a lower LWT setpoint. But I only have one chiller (for now, they're going to add another) so I'm screwed.

So, how long can this thing surge like a locomotive before the compressor is toast?

No load is no load is no load and no chiller no matter how many bells and whistles you put on it or into the programme that controls it can change that . SHUT THE FREAKIN THING OFF !!!!!!!!!!....or generate sufficient load to keep it happy .

As for how long it will run before self distruction ......... is that really relevant ???